Manufacture of printed articles



May 23, 1944,

H 2,349,718 FRIEDRICH-WILHELM G. GRAVENSTEIN MANUFACTURE OF PRINTED ARTICLES Filed May 24, 1940 I 2 Sheets-Sheet 1 3 m iww QM i? nm N 0 0 Wm Q 0 o Ill 7 N n v c g I 0 MN QN I FRIEDRICH-WILHELM e. GRAVENSTEIN MANUFACTURE OF PRINTED ARTICLES Filed Il ay 24, 1940 2 Sh eets?Sheet 2 I l I l l l I l. I I

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Patented May 23, 1944 MANUFACTURE OF PRINTED ARTICLES Friedrich-Wilhelm Georg Gravenstein, Berlin, Germany, assignor to Transart Aktiebolag, Goteborg, Sweden, a corporation of Sweden Application May 24, 1940, Serial No. 337,08? In Sweden March 1, 1940 2 Claims.

' This invention relates to a rotary printing press for the manufacture of printed articles comprising a collection of flexible glass clear leaves standing in a certain relation to one another and carrying on both sides thereof nontransparent double pictures presenting different images, when viewed from the front and from the back of each leaf, said images being disposed at least partly within the same contour. The leaves of the collection may be connected to form a book, a booklet or the like, or may be disposed in a holder or a case, by means of which the'different leaves are kept in the desired register relatively to each other. In this collection of leaves, in which the leaves are provided with for example different pictures visible within the same contours, one from one side and the other from the other side thereof, a plurality of composite pictures are presented as the leaves are turned, the left hand collection of leaves presents one picture and the right hand collection of leaves a further picture, the former formed by the back of the leaves and the latter by the front thereof.

It may be easily understood that the mechanical reproduction of such picture collections or picture books has resulted in entirely new problems due to the necessity of maintaining the most accurate register between the double pictures of the different leaves and between the pictures of each separate leaf. Such problems are not encountered in the known methods of reproducing pictures, whereas in the manufacture of the printed articlesaccording to th invention said problems must be carefully considered with respect to the production of the original pictures, the reproduction thereof and the manufacture of the printing moulds as well as particularly with respect to the nature of the transparent material and the ink employed in printing, and further also with respect to the constructive form, and the separate apparatus and means in the rotary printing press employed in the printing operation.

The production of the original pictures, the reproduction thereof, and the manufacture of the printing moulds are the subject of a separate patent application.

One object of the present invention is to provide a rotary printing press for printing or manufacturing printed articles of thetype described hereinbefore in which the printing moulds manufactured by photomechanic or other methods are printed on a continuous web of flexible glass clear artificial foil, single pictures or double pictures being applied simultaneously at both sides of the web during one passage of operation of the machine. The web is then cut in sheets each carry ing one or several double pictures, and the sheets intended to form the collection should be assembled to bring the pictures in accurate register relatively to each other to form said printed article as required.

A further object of the invention is to provide a rotary printing press adapted for printing or producing printed articles of the type referred to, and which comprises on one hand, intaglio printing units for printing one side of the leaf, and on the other hand intaglio or relief printing units for printing the opposite side of the leaves, means for pulling the web through the press, means for cutting the web to sheets, and a table for depositing said sheets. However, it is possible to use a rotary printing press of a similar construction but provided with only intaglio printing units for printing both sides of the leaves. When the intaglio printing process is used, the etch depth may be the same as in intaglio printing on plain paper.

Further details and features of my invention will be clear from the following description and claims.

The print carrier As above stated the printing moulds are printed in a printing press on a continuous web of glass clear artificial foil. The material of this foil may, for instance, comprise different derivatives of cellulose, but I prefer to use acetyl cellulose, particularly diand tricellulose acetate, which are perfect materials for such foils. Said material gives an absolutely glass clear high flexible foil, which is resistant to atmospheric influences including the high temperatures prevailing in tropical countries and which has reduced fusibility and may be washed. The foil also has great permamency of size, which is a very important feature for the precision of the printing operation, since the pictures on each leaf and on different leaves must register accurately. The tensile curve of the material runs practically horizontal between the yield point and the ultimate tensile strength. This property is utilized in the printing process to obtain high degree of size permanency by feeding the foil web through the printing press under certain tension, thereby causing the web during and after the printing operation to maintain the elongation obtained by said tension and to remain very permanent with respect to size.

The cellulose material used in the manufacture of the acetyl cellulose should have a high acetyl number, and in order to obtain the desired properties in the finished foil only small quantities of plasticising agents or other additions are necessary. In the manufacture of the acetyl cellulose, fir, pine, beech or the like may be used. A particularly suitable material is cotton linters, .i. e. waste from cotton plants.

As I have stated hereinabove acetyl cellulose foil is also preferred as carrier for the original pictures.

The foil used as print carrier is produced in long continuous webs by casting on an absolutely even, high polished metallic surface, for instance a copper roller. Great pain should be taken to keep the thickness of the material constant. I prefer to use a foil having a thickness between 0.04 and 0.06 millimeter and a weight between 50 and 84 grams per square meter. In order to ensure an even tension of the foil web during the printing operation the largest breadth of the web should not exceed 650 millimeters, since if this measure is exceeded distortion may occur during the passage of the Web through the different printing units.

Before the application of the picture on the foil I prefer to treat the foil surface with an agent which slightly attacks said surface and makes it rough and thereby facilitates the application of the printing ink. Such an agent may be a material, which chemically attacks or solves the acetyl cellulose foil, for instance a ketone such as acetone. This agent may be applied to the foil web separately, for instance by means of a roller, but I prefer to mix the agent with the printing ink. When the non-transparent pictures are produced by using one or more separating or ground layers of substantially opaque character and said layer is applied directly on the foil surface, the agent may preferably be mixed in the printing ink employed for the production of said layer.

The printing process The printing of the moulds may be achieved by any known method but I prefer the intaglio printing process and/or the acrcgraphic or relief printing process (book print), particularly only the intaglio process, since said process gives very clear pictures on artificial foil with sharp outlines and completely solid picture areas. The process is preferably carried out in a rotary printing press.

In the accompanying drawings Figs. 1 and 2 illustrate two embodiments of a suitable rotary printing press by way of example, said presses being particularly adapted for printing two opaque bottom or ground layers and a picture in not more than four colours on each side of the foil. The reason for using two ground layers is the more complete opacity obtained thereby.

The rotary printing press according to Fig. 1 comprises a lower set including six intaglio printing units II, l2, l3, l4, l5 and i6 and an upper set including four acrographic printing units; 1?, l8, l9 and 28. The two first intaglio printing units II and I2 are employed for printing the separating layers and the four subsequent intaglio printing units l3i6 for printing a four colour picture on one side of the foil, whereas the aerographic printing units ll-2fl ar employed for printing a four colour picture on the other side of the foil. The printing is carried out on an acetyl foil Web, which is fed from one of two reels 22 or 23. It has been found convenient to provide two reels so that when one reel is finished the foil web of the other reel may immediately be secured to the end of the previous web. A saving of material and any distortion of the web is thereby obtained. Every intaglio printing unit is provided with a combined heating and drying apparatus comprising, for instance, an electrically heated drum 24, over which the freshly printed web is fed with the non-printed surface against the drum, and having a sheet metal hood 25 or the like provided thereon, in which according to the properties of the printing ink cold or hot air is blown against the printed surface of the web to accelerate drying. Every acrographic printing unit is provided with a drying apparatus 26, which may be supplied with hot or cold air according to the properties of the printing ink. 27 designates a pulling device, by means of which the foil as above stated may be fed through the printing press with a certain tension. 28 is a. cutting device, 29 a pneumatic foil sheet or leaf guiding device, and 3d a table for depositing the cut sheets or leaves. Before cutting the sheets or leaves in the cutting device 28 a paper web 3| is fed into contact with the foil web from a reel 32 in order to facilitate the separation of the different sheets or leaves, which are often strongly loaded with electricity. In order to facilitate the separation of the sheets or leaves the edges or corners of the separate sheets or leaves may furthermore be provided during the printing operation with indicia or marked portions of different shapes in a manner known per se. The foil web 2! and the paper web 3! are cut simultaneously in the cutting device 28.

The foil web is led the shortest possible path through the press and guided in such a manner that an even tension of the web is ensured and that every distortion in the longitudinal or transverse direction of the Web is avoided.

The printing ink of different colours and particularly the printing ink used in the units II and I2, which produce the separating or ground layer, is preferably mixed with the above mentioned agent, which serves to make the surface of the foil rough in the printed areas. In order to accelerate the drying which, naturally, takes more time in printing on artificial foil than in printing on paper, the printing ink of the intaglio printing units may be mixed with an easily volatile solvent, for instance xylol, toluol or the like, and the printing ink in the acrographic printing units with a siccative or metallic drying pastes.

The combined intaglio and acrographic printing press has the advantage that the plates of the acrographic printing rollers may be made to conform with the rigid intaglio printing cylinders. Since, however, the drying of the prints made in the acrographic printing section of the press involves certain difficulties, and a more clear print on artificial foil and more distinct pictures are obtained by the intaglio printing process than by the acrographic printing process I sometimes prefer to use intaglio printing units throughout the entire press as illustrated in Fig. 2.

In this press the lower set of printing units is arranged in the same manner as above described and comprises intaglio printing units, whereas the four acrographic printing units illustrated in Fig. 1 are replaced by four intaglio printing units 33, 34, 35 and 36 provided with combined heating and drying devices 24 and 25.

In order to enable the separating or bottom layer to be printed at will on both sides of the foil or on the front side or the back side of the foil one or both printing units H and i2 may be made reversible as indicated in dotted lines in connection with the unit ll in Figs. 1 and 2. I

In both printing presses illustrated in the drawings mechanically or electrically driven roller ad- Justin-g means may be provided for adjustment of the separate printing units as well as for mutual adjustment of the six lower and the four upper printing units.

In order to avoid as much as possible subsequent adjustments or corrections of the printing moulds at the final adjustment of the press I prefer to make copies of the separate ready etched printing cylinders before they are mounted in the rotary press, and I make such copies in a separate complete intaglio printing press. The time and work used in making such test copies is compensated by the reduction of time for adjustments and the reduced loss of artificial foil.

What I claim is:

1. A rotary printing press for manufacturing a plurality of printed articles comprising a collection of leaves of flexible glass clear material carrying non-transparent double pictures presenting, when viewed from one side of a leaf or the other, different images disposed at least partly within the same contour, intaglio printing units for printing one picture of a double picture for a leaf on one side of a continuous web of said material, acrography printing units for printing the other picture of said double picture on the other side of said web, drying means supplied with drying air in each acrography printing unit, and means for pulling the web under even tension through the printing units disposed posteriorly of said printing units with respect to the feeding direction of the web.

2. A rotary printing press for manufacturing a plurality of printed articles comprising a collection of leaves of flexible glass clear material carrying non-transparent double pictures presenting, when viewed from on side of a leaf or the other, diiferent images disposed at least partly within the same contour, four intaglio printing units in said printing press for printingv one picture of said double pictures for a leaf on one side of a continuous web of said material, four rotary printing units for printing the other picture of the double pictures for the leaf on the other side of said web, and means for pulling said glass clear flexible foil web under even tension through the printing units.

FRIEDRICH -WILHELM GEORG GRAVENSTEIN. 

